The present invention relates to a golf ball of improved performance which includes, in a polymer layer making up the golf ball, a layer that has been treated by impregnation with an isocyanate group (here and below, “isocyanate group” encompasses also “isothiocyanate group”)-containing olefin compound.
Organic reactive compounds are useful materials in golf balls made with thermoplastic and thermoset polymer materials. Of such compounds, isocyanate group-containing compounds in particular, when blended with a polymer material, are able to modify the properties of the polymer material, and have thus been useful compounds as golf ball modifiers.
Organic reactive compounds are commonly included in polymer materials for golf balls for a variety of purposes. For example, organic peroxides such as dicumyl peroxide and di-t-butylperoxide, epoxy compounds such as bisphenol A diglycidyl ether and polyethylene glycol diglycidyl ether, and acrylate compounds such as 1,4-butanediol diacrylate and triethylene glycol diacrylate are used for crosslinking between polymer molecules. Various compounds, including acid anhydrides such as maleic anhydride and itaconic anhydride, silane compounds such as silsesquioxane oligomer and POSS, and isocyanate compounds such as toluene diisocyanate and 4,4′-diphenylmethane diisocyanate, are used in the presence of a peroxide for the purpose of introducing functional groups onto polymer molecules. Numerous patent applications have been filed concerning the use of such compounds.
Examples include the following, all for the purpose of crosslinking between polymer molecules: Patent Document 1 (U.S. Pat. No. 7,387,821) and Patent Document 2 (U.S. Pat. No. 7,387,582) relating to the use of an organic peroxide, Patent Document 3 (U.S. Pat. No. 5,908,358) and Patent Document 4 (U.S. Pat. No. 7,358,310) relating to the use of an epoxy compound, Patent Document 5 (U.S. Pat. No. 7,151,148) and Patent Document 6 (U.S. Pat. No. 7,001,286) relating to the use of an acrylate compound, Patent Document 7 (U.S. Pat. No. 6,890,661) and Patent Document 8 (U.S. Pat. No. 7,029,405) relating to the use of an acid anhydride, Patent Document 9 (U.S. Pat. No. 6,585,607) and Patent Document 10 (U.S. Pat. No. 6,919,395) relating to the use of a silane compound, and Patent Document 11 (JP-A 11-178949) and Patent Document 12 (JP-A 2008-049152) relating to the use of an isocyanate compound.
As noted above, almost all conventional methods for using organic reactive compounds in the field of golf balls involve blending those compounds with various polymer materials at some stage prior to molding golf balls, thereby modifying the functions of the polymer materials and causing such changes to be reflected in the performance of the molded golf balls.
Yet, a desire has arisen recently for even further improvement in the performance of molded golf balls, such as the feel of the ball on impact, scuff resistance, spin and distance. It is customary to conduct studies on improvements in golf ball performances by reexamining the various polymer materials making up the balls. By contrast, with the exception of certain patents relating to partial surface modification (Patent Document 13: U.S. Pat. No. 6,458,307; Patent Document 14: U.S. Pat. No. 7,381,776), very few of any specific measures targeted at molded golf balls or golf balls in the process of being molded have been employed to date. Hence, this remains an area of untapped potential.
Patent Document 1: U.S. Pat. No. 7,387,821
Patent Document 2: U.S. Pat. No. 7,387,582
Patent Document 3: U.S. Pat. No. 5,908,358
Patent Document 4: U.S. Pat. No. 7,358,310
Patent Document 5: U.S. Pat. No. 7,151,148
Patent Document 6: U.S. Pat. No. 7,001,286
Patent Document 7: U.S. Pat. No. 6,890,661
Patent Document 8: U.S. Pat. No. 7,029,405
Patent Document 9: U.S. Pat. No. 6,585,607
Patent Document 10: U.S. Pat. No. 6,919,395
Patent Document 11: JP-A 11-178949
Patent Document 12: JP-A 2008-049152
Patent Document 13: U.S. Pat. No. 6,458,307
Patent Document 14: U.S. Pat. No. 7,381,776